Battery won't keep a charge?

I've had this truck for about a month. I opened the drivers door and set off the alarm and now the battery doesn't keep a charge. Ive check every fuse, glove compartment lite, inter light, sat in the truck and listened for anything running, nothing. I have to jump it off in the AM to go to work and has the be jumped 8hrs later to come home. This all started when the security system went off. Thanks in advance for hour help.